The present application relates generally to the field of airbags and occupant protection systems. More specifically, the application relates to a mounting device for mounting an airbag module, such as a side impact airbag module, to a seat frame member.
Side impact airbag devices may be provided in vehicle seats, such as the front seats of the vehicle. Side impact airbag devices or modules may be mounted on either the outboard or inboard (i.e., center) side of the vehicle seat. The center side impact airbag is configured to deploy away from the seat to dampen the displacement of the occupant in the inboard direction in the event of a vehicle side impact and to transfer the load of the occupant to the seat frame.
A mounting bracket for an airbag module typically includes a plate with threaded studs extending from the inboard side of the plate. The studs are inserted into openings in a seat frame, and a nut engages the studs on the opposite side of the seat frame from the plate. The nut is tightened down to couple the mounting bracket to the seat frame. When the airbag is deployed and the occupant travels in the inboard direction into the airbag, the lateral load caused by the occupant is transferred from the airbag, through the mounting bracket, and to the seat frame over the surface area of the bracket. The dimensions of the bracket also determine the length of the moment arm formed by the attached inflated cushion and the occupant shoulder contact point (e.g., the distance from the shoulder contact point to the front edge of the mounting bracket). This moment arm affects the restraint capacity of the airbag. The bracket is also configured to withstand the forces generated during the deployment of the airbag when the inflator inflates the cushion at a rapid rate.
However, the clamping load that couples the bracket to the seat frame and withstands the force of the deployment of the airbag is limited by the size of the studs and nuts used to couple the bracket to the seat frame. The load is therefore not distributed over a large area and places excessive stress on a local portion of the seat frame adjacent the nut. Further, the bracket engages the seat frame with a relatively small area. The size of this area is generally limited by the size and configuration of the seat frame, as increasing the area of the bracket may interfere with other functionalities of the seat.
Modern vehicle seat frames may be designed to minimize weight and cost by decreasing material thickness, removing welds, reducing components, and optimizing seat profiles. However, such design considerations may weaken the structural integrity of the vehicle seat. Thus, there is a need for improved load distribution from the airbag to the seat frame.